91 PA a/c driving me nuts

a/c is blowing nothing but hot air . the instruments are going nuts. speedo and tach are way off. showing 6000 rpm at idle, voltmeter is on 0. oil pressure on 2, coolant in the center, and they all keep vibrating, and swinging to the left and right . the service engine light and inflatable restraint stay on after starting the car, just flickering. after a while they go off, and the abs light comes on and stays on. the a/c unit shows numbers on the display, but i can't turn it on or off either, and sometimes the display is all dark. and i get full heat at full blower speed blowing in my face, killing me...

any ideas ?
oh, and relays under the dashboard and inside the engine compartment, keep clicking like crazy.... (defog realy under the dash mostly, already switched relays, no effect)

Look for bad connections at the battery- or a bad body ground wire at the battery-- corrosion can cause this type of activity- especially on the ground side....

connections at the battery are clean, checked for bad looking wires, can't seem to find any...

Did you check the 12v power cable feeding the fuse/relay center on the firewall? How about the 12v feed from the alternator? Remember to disconnect the negative (-) battery terminal first, before working in these areas!

thay all seem fine.

(defog realy under the dash mostly, already switched relays, no effect)Have you checked the circuit breakers in the main fuse panel? Are they getting hot? Pull them out and look at the terminals inside the fuse panel. In fact, remove the circuit breaker for the defog and see what happens.

Have you checked the circuit breakers in the main fuse panel? Are they getting hot? Pull them out and look at the terminals inside the fuse panel. In fact, remove the circuit breaker for the defog and see what happens.
sorry was away for a while...
do you mean the 3 silver ones on the driver side fuse panel? yes they are getting hot.

do you mean the 3 silver ones on the driver side fuse panel? yes they are getting hot. Yes, those are the ones. These should only get "hot" with a load on them. Remove the one for the defrost and see what happens. Click Here (http://www.automotiveforums.com/vbulletin/showthread.php?t=639799) for some more info.

BTW, Have you check the ground bus under the carpet? Click Here (http://www.automotiveforums.com/vbulletin/showthread.php?t=902658)

great, came back to the car this morning only to find out everything seemed to work normal. but cause i didn't trust the car (it fooled me before,lol). i cleaned the ground bus, it was a little corroded. kept turning the car on and off, and the situation went back to messed up after a few on/offs. i pulled the breaker when the mess started again(gauges not working, ac programmer not lit) but nothing changed. after a while everything went back to normal. i noticed that the a/c light/programmer was on, but the compressor wasn't kicking in, so i tried the ecc ovveride command to turn the compressor on, nothing, wouldn't come on. i had previously checked the values for the controller, and everything read out to what i found in the electric manual. so this thing is killing me. wonder i fi should replace all circuit breakers? haven't done that yet.

problem fixed.
the car had indeed a ground issue. after cleaning up ALL ground locations on the car, and boy there are plenty. the car still wouldn't work. up until i stumbled upon a spliced wire. for whatever reason one of the previous owners decided to extend a ground wire inside the engine compartment, and only used a crimp connection. so over time, you guessed it the connection oxydized and caused everything to work eratically. so i got rid of the crimp connection, and voila! works like a charm again.

Good feedback & thanks! Glad to here you found the problem. Everything electrical on the vehicle depends on a good ground to complete the circuit. BTW, where did the "spliced wire" terminate? (Location)

believe it or not, near the battery. and the douche that extended the wire used a red colored wire to extend the black ground wire, just one reason why i didn't notice it right away. the car also has two of those ground bus connectors, one on the driver and one on the passenger side, just in case other folks are looking for them.
and it sure is amazing how a tiny spot of oxydation can cripple the entire car.